Author Topic: EEVsmoke #2  (Read 16191 times)

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Offline amirm

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Re: EEVsmoke #2
« Reply #25 on: November 09, 2016, 05:49:21 pm »
Anyone have some good examples of a MOV failure?
Here you go:



 

Offline bktemp

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Re: EEVsmoke #2
« Reply #26 on: November 09, 2016, 06:24:11 pm »
Anyone have some good examples of a MOV failure?
Here you go:


What is this device that needs so many MOVs? And what is the black thing with the toriodal core on top of it?

Whenever metal vaporises, it leaves a horrible mess.
That's why you need HRC fuses for multimeters, because cheap glass fuses can explode while trying to interrupt a full mains short.
 

Offline blueskull

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Re: EEVsmoke #2
« Reply #27 on: November 09, 2016, 11:21:31 pm »
And what is the black thing with the toriodal core on top of it?

Maybe a connector? So that wire coming out of it goes through the core, and the core serves as a current sensing transformer.
 

Offline Brumby

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Re: EEVsmoke #2
« Reply #28 on: November 10, 2016, 01:54:43 am »
Ah!  Found the pics I took of my MOV drama:

The direct view....


From above (with enhancement)


The PCB after cleaning...


The casualties:  (Yes, everything in the yellow frame is was the MOV):
« Last Edit: November 10, 2016, 02:03:45 am by Brumby »
 

Offline Brumby

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Re: EEVsmoke #2
« Reply #29 on: November 10, 2016, 02:00:18 am »
Dave - I'll send the Hi-Res to you ... in case you are interested.
 

Offline amirm

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Re: EEVsmoke #2
« Reply #30 on: November 10, 2016, 03:09:37 am »
What is this device that needs so many MOVs? And what is the black thing with the toriodal core on top of it?
It is a service entrance/whole house SPD (surge protection device).  I assumed they paralleled the MOVs to get higher energy absorption capacity.

Quote
That's why you need HRC fuses for multimeters, because cheap glass fuses can explode while trying to interrupt a full mains short.
That's right.  Many of these SPDs unfortunately have no fuse so when the MOV goes, it goes really bad.
 

Offline Fungus

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Re: EEVsmoke #2
« Reply #31 on: November 10, 2016, 10:30:23 am »
Ah!  Found the pics I took of my MOV drama:

Now you know why some people wrap them with heatshrink....  :popcorn:

 

Offline Mike Warren

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Re: EEVsmoke #2
« Reply #32 on: November 10, 2016, 10:55:13 pm »
From quite a few years ago. The magic smoke had escaped, but it wasn't particularly dramatic. Looks like the mouse could smell fried lizard.


 
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Offline guido

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Re: EEVsmoke #2
« Reply #33 on: November 11, 2016, 01:54:14 am »
There's also magic liquid. One cap turned ballistic and tried to lift off.



Got it working again, it's an off the shelf powersupply in a Kode time interval analyser.
 

Offline strawberry

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Re: EEVsmoke #2
« Reply #34 on: November 21, 2016, 06:24:47 pm »
From some old TV 80's
 

Offline iwasz

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Re: EEVsmoke #2
« Reply #35 on: March 13, 2017, 07:29:03 pm »
Mains went through USB port. Pictured below is an ESD protection IC.
 

Offline Nobody2

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Re: EEVsmoke #2
« Reply #36 on: March 14, 2017, 11:52:30 am »
From quite a few years ago. The magic smoke had escaped, but it wasn't particularly dramatic. Looks like the mouse could smell fried lizard.


:wtf:
And what's the mouse doing there? Or where both the mouse and the lizard fried? How did they get in there in the first place?!?
 

Offline EPTech

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Re: EEVsmoke #2
« Reply #37 on: December 30, 2017, 01:03:40 pm »
Hi there,

I was repairing a VFD and got another power IGBT module with a blown up brake chopper, massive gate failure. The TVS over the gate and emitter took the over voltage like a boss, shorted out and the mostfet driver seems to have survived thanks to the series resistor to the gate. Although not as impressive as OP picture, The magic smoke got caught in the act. Additionally you can see the bonding wires melted off the emitter, just below the black spot. The intense heat also boiled the gel around the area.
Kind greetings,

Pascal.
 

Offline Mike Warren

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Re: EEVsmoke #2
« Reply #38 on: January 02, 2018, 08:10:54 am »
From quite a few years ago. The magic smoke had escaped, but it wasn't particularly dramatic. Looks like the mouse could smell fried lizard.


:wtf:
And what's the mouse doing there? Or where both the mouse and the lizard fried? How did they get in there in the first place?!?

Sorry, I missed this. Both animals had been killed by touching the 240V terminals. My guess is that the mouse smelled fried lizard and went to get some to eat.
 

Offline blueskull

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Re: EEVsmoke #2
« Reply #39 on: January 02, 2018, 09:11:56 am »
Ironically the gecko could use some life insurance.
 

Offline madsbarnkob

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Re: EEVsmoke #2
« Reply #40 on: January 04, 2018, 09:40:10 am »
80k views, 5k thumbs, and a normal 5% thumbs down ratio.
So the segment seems very popular.
Although it could still be anomaly because of the awesome captured smoke photo.

I am happy that you like my photo and contribute it some success, it was however sent in by someone that has seen it on my website and did not include proper credits for it.

Please link back to my original article where the photo is from: http://kaizerpowerelectronics.dk/technology/teardown-schneider-electric-frequency-inverter-altivar71/

On your question on how the layers of smoke settled in the gel has happened, it is my thesis that the long and flat flower like black paths in the goo is actually the gasses from the  exploded IGBT die, the gas expands out into the goo that blows a bubble and collapses as soon as the pressure is gone. Leaving a black trail of burned silicon, metal and goo.
http://www.kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power and more :)
http://www.highvoltageforum.net - Dedicated high voltage / Tesla coils forum
 


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